Transient Snap-Through of a Bistable Composite Laminate Under Asymmetric Point Load

Bistable fiber composite laminates have promising capabilities for shape morphing and have found applications in advanced airframes, energy harvesting, and robotics. Their bistability originates from an asymmetric ply layout and can create highly complex deformations during the snap-through from one stable state to the other. Therefore, it is essential to understand the transient behaviors of these laminates under different loading conditions. Although simple symmetric loading conditions are well understood, asymmetric loading conditions received far less attention. In this study, we investigate the transient deformation of a [0 degrees/90 degrees] square laminate subjected to an asymmetric point load at different locations. Finite element simulation and experimental testing both show that, depending on the loading position, snap-through can either be a one-step or two-step process, while each step is related to the curvature change of a laminate edge. Also, at some loading positions, snap-through is unattainable regardless of the input magnitude. The results of this study would help us obtain a more comprehensive understanding of the nonlinear mechanics of bistable composite laminates showing transient response to different external forces.